Electrode seal



y 1941- s. A. HARDIN 2,243,096

ELECTRODE SEAL Filed June 29, 1939 2 Sheets-Sheet 1 FIG. I

Sfanford A. Hard: IN VEN TOR BY ATTORNEY y 7, 1941. s. A. HARDIN 2,243,096

ELECTRODE SEAL Filed June 29, 1959 2 Sheets-Sheet 2 FIG. 2

Stanford A. Haro'm INVENTOR B Wan-ML ATTORNEY Patented May 27, 1941 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) Claims.

The invention herein described may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a seal for movable electrodes in electric furnaces.

In the operation of electric furnaces in which some of the products produced therein are toxic or where the admission of atmospheric air is detrimental to furnace operation or subsequent operations, it is necessary to provide such furnaces throughout with fluid impervious seals. The principal problem in the construction and operation of such furnaces is to provide such a fluid impervious seal around the electrodes at all times as they are moved into the furnace as a result of consumption of the electrode or portions of the electrode withdrawn from the furnace when extensions are required. Many proposals have been made covering various combinations of apparatus elements for accomplishing this result satisfactorily but installations made in accordance with such proposals usually have one or more serious disadvantages.

One of the objects of this invention is to provide an effective seal against the admission of atmospheric air into an electric furnace or the passage of furnace gases from the furnace around the respective electrodes passing through the furnace shell. Another object of this invention is to provide a seal for electric furnace electrodes which is not affected in its operation by material which may be deposited from the gases produced within the furnace. Still another object of this invention is to provide an electric furnace electrode seal which does not cause electrical disturbances within or without the furnace due to its presence. Other objects of this invention include the provision for an efficient and economical apparatus for sealing electrodes passing through a furnace shell wherein the electrode is continuously or periodically moved, to compensate for the change in electrical resistance of the charge inside the furnace.

I have discovered a novel apparatus for fluid imperviously sealing the opening between a movable electrode through a furnace roof without the passage of fluid from said furnace between said electrode and said roof, in the combination which comprises a liquid cooled outer chamber around said electrode, a plurality of concentric liquid cooled inner chambers within said outer chamber, means for maintaining a predetermined liquid level in each chamber, means for respectively engaging and disengaging adjacent chambers as said seal is respectively extended and contracted, and means for connecting the top of the innermost chamber with said electrode and said outer chamber with said roof. Such combination may be employed with or without the means for admitting inert gas between said seal and said electrode to prevent the admission of or deposition of volatile products from the furnace to the zone between the seal and the electrode.

In the accompanying drawings which form a part of the specification and wherein reference symbols refer to like parts wherever they occur.

Fig. 1 is a half plan, half sectional plan view of one form of apparatus for the embodiment of my invention,

Fig. 2 is a half sectional, elevational view of the apparatus shown in Fig. 1.

In Fig. 1 and Fig. 2 an electrode I supported by an electrode holder 3 passes through an opening in a furnace roof 5 and is fluid imperviously sealed in an extensible and contractable electrode seal 1. The primary chamber 9 of the electrode seal 1 is a ring casting adapted to fit securely in the opening in furnace roof 5 and to permit electrode l to move freely therethrough. One ormore slidable inner chambers, represented by secondary chamber H and tertiary chamber l3 are located within primary chamber 8. The upper end of chamber I3 is engaged fluid imperviously to electrode I by an adjustable clamp I5 which. in this embodiment. is supported to electrode holder 3 by a plurality of hangers. represented by hanger ll. Suitable packing, such as asbestos, is inserted between clamp 15 and electrode i and between chamber I3 and adjustable clamp l5, as represented by packing l9 and packing 2|. Cool mg water enters the seal 1 through a plurality of cooling water inlet pipes, represented by inlet 23, fills chamber 13 to the top of a plurality of overflow pipes, represented by overflow 25, cooling water from overflow 25 then fills chamber II to the top of a plurality of overflow pipes represented by overflow 21, and cooling water from overflow 21 then fills chamber 9 to the elevation of a plurality of cooling water outlet pipes represented by outlet 29. By this arrangement of inlets, overflows, and outlets each chamber of the sea] I is maintained full of water when the seal I is either extended or contracted. 'As the electrode holder 3 is raised by suitable hoisting means (not shown) attached to a plurality of engaging members. represented by engaging member 3|, as periodically required for the relocation of electrode holder 3 on electrode I,

chamber I3 is raised therewith and a plurality of stop lugs, represented by lug 33 engages a stop ring 35 on chamber II and subsequently upon further upward movement of electrode holder 3, a plurality of stop lugs, represented by lug 31 engages a stop ring 39 on chamber 9 thereby determining the maximum path of travel of electrode holder 3 and the maximum length of elec trode l which may be consumed before relocation of electrode holder 3 thereon. As electrode 1 is consumed and electrode holder 3 is lowered from its maximum height chamber ll comes to rest on a ring 4| integral therewith and subsequently chamber l3 comes to rest on ring 43 integral therewith. An inert gas inlet 45 is provided through that part of chamber l3 above ring 43 to provide for maintaining the space between the electrode l and the seal 1 with a pressure of inert gas equal to or slightly greater than the pressure within the furnace, thereby increasing the effectiveness of the seal in eliminating air from the furnace, particularly to prevent any accidental admission of air to the furnace or furnace gases should the fluid impervious seals heretofore referred to be imperfectly assembled. The cooling water inlets and outlets are connected to a supply header (not shown) and a discharge header (not shown) with the former supplied with a flexible connection for accommodating the movement of the electrode I and electrode holder 3. The inert gas inlet 45 is likewise supplied with a flexible connection from a suitable source of supply.

It is evident that there are numerous factors which will influence conditions for the most satisfactory operation of my apparatus, the actual limits of which cannot be established except by a detailed study of each type of furnace and electrode to which it will be applied, as well as the nature of the material produced in the furnace which may come in contact with parts of the electrode seal.

In the preferred embodiment of this electrode seal, the outer chamber is made of non-magnetic cast iron and the two inner chambers are made of light stainless steel plate or similar material to eliminate magnetic induction and also to minimize the total weight of the seal.

The ultimate sealing to prevent passage of gaseous material is effected by the presence of liquid within the respective chambers. Means are provided for admitting liquid, such as water, into the top of the innermost chamber. The depth of liquid in such chamber is determined by the position of an overflow therein which communicates with the adjacent chamber externally thereto except in the case of the outermost chamber wherein an outlet is provided for discharge of the residual sealing liquid. Each of the inner chambers is provided with exterior lugs which respectively limit the extent of movement of such chamber in respect to such adjacent external chambers. The position of the respective lugs defines the depth of the liquid seal and consequently the amount of pressure variation which may be permitted and still maintain complete sealing of the furnace. A sufiicient number of liquid inlets are provided to insure a uniform supply of liquid to the seal as required, and, likewise, a sufficient number of liquid outlets are provided to insure a suitable discharge for the sealing liquid which also serves to cool the seal.

The combination of elements which make up the seal proper must be sealed to the furnace elements between which relative motion takes place. The exterior chamber is fluid impervi ously sealed into an opening in the roof of the furnace while the top of the innermost chamber is connected to and fluid imperviously sealed to an electrode. The seal is attached to the electrode by an adjustable clamp associated with the innermost chamber and is attached to the furnace roof by sealing the outer chamber into the opening in the furnace roof with refractory mortar. Asbestos may be utilized in and about the seal as is necessary to insure fluid impervious connections between the various elements of the seal and its connection to the electrode and furnace roof. One or more inlets for gas, which is inert in respect to the furnace contents, may be provided as required to the zone between the seal and the electrode. In certain instances, the use of such gas is not required while in other instances the use of such gas may be required to prevent the deposition of condensable furnace products in said zone.

It will be seen, therefore, that this invention actually may be carried out with a number of variations without departing from its spirit and scope.

I claim:

1. In a liquid seal adapted to permit movement of an electrode through an opening in a furnace roof without the passage of fluid from said furnace between said electrode and said roof, the combination which comprises a primary chamber around said electrode, a movable secondary chamber within said primary chamber and extending therefrom, a movable tertiary chamber within said secondary chamber and extending therefrom, a liquid inlet into the top of said tertiary chamber, a plurality of liquid conducting elements extending from the top to the bottom of said tertiary chamber and com municating with said secondary chamber, a plurality of liquid conducting elements extending from the top to the bottom of said secondary chamber and communicating with said primary chamber, a liquid outlet near the top of said primary chamber, a plurality 01 elements attached to the exterior of said tertiary chamber and said secondary chamber adapted to respectively engage the top of said secondary chamber and said primary chamber as said seal is extended, elements attached to the exterior of said secondary chamber and said tertiary chamber adapted to respectively engage the top of said primary chamber and said secondary chamber as said seal is contracted, means for connecting the top of said tertiary chamber with said electrode and said primary chamber with said roof, and means for admitting fluid between said electrode and said seal.

2. In a liquid seal adapted to permit movement of an electrode through an opening in a furnace roof without the passage of fluid from said furnace between said electrode and said roof, the combination which comprises a primary chamber around said electrode, a movable secondary chamber within said primary chamber and extending therefrom, a movable tertiary chamber within said secondary chamber and extending therefrom, a liquid inlet into the top of said tertiary chamber. a liquid conducting element extending from the top to the bottom of said tertiary chamber and communicating with said secondary chamber, a liquid conducting element extending from the top to the bottom of said secondary chamber and communicating with said primary chamber, a liquid outlet near the top of said primary chamber, elements attached to the exterior of said tertiary chamber and said secondary chamber adapted to respectively engage the top of said secondary chamber and said primary chamber as said seal is extended, elements attached to the exterior of said secondary chamber and said tertiary chamber adapted to respectively engage the top of said primary chamber and said secondary chamber as said seal is contracted, means for connecting the top of said tertiary chamber with said electrode and said primary chamber with said roof, and means for admitting fluid between said electrode and said seal.

3. In a liquid seal adapted to permit movement of an electrode through an opening in a furnace roof without the passage of fluid from said furnace between said electrode and said roof, the combination which comprises a primary chamber around said electrode, a movable secondary chamber within said primary chamber and extending therefrom, a movable tertiary chamber within said secondary chamber and extending therefrom, a liquid inlet into the top of said tertiary chamber, at least one liquid conducting element extending from the top to the bottom of said tertiary chamber and communicating with said secondary chamber adapted to maintain a predetermined head of liquid in said tertiary chamber, at least one liquid conducting element extending from the top to the bottom of said secondary chamber and communicating with said primary chamber adapted to maintain a predetermined head of liquid in said secondar chamber, a liquid outlet near the top of said primary chamber, elements attached to the exterior of said tertiary chamber and said secondary chamber adapted to respectively engage the top of said secondary chamber and said primary chamber as said seal is extended, elements attached to the exterior of said secondary chamber and said tertiary chamber adapted to respectively engage the top of said primary cham ber and said secondary chamber as said seal is contracted, and means for connecting the top of said tertiary chamber with said electrode and said primary chamber with said roof.

4. In a liquid seal adapted to permit movement of an electrode through an opening in a furnace roof without the passage of fluid from said furnace between said electrode and said roof, the combination which comprises a primary chamber around said electrode, a movable secondary chamber within said primary chamber and extending therefrom, a movable tertiary chamber within said secondary chamber and extending therefrom, a liquid inlet into the top of said tertiary chamber, liquid communicating means between said tertiary chamber and said secondary chamber adapted to maintain a predetermined head of liquid in said tertiary chamber, liquid communicating means between said secondary chamber and said primary chamber adapted to maintain a predetermined head of liquid in said secondary chamber, a liquid outlet near the top of said primary chamber, elements attached to the exterior of said tertiary chamber and said secondary chamber adapted to respectively engage the top of said secondary chamber and said primary chamber as said seal is extended, elements attached to the exterior of said secondary chamber and said tertiary chamber adapted to respectively engage the top of said primary chamber and said secondary chamber as said seal is contracted, and means for connecting the top of said tertiary chamber with said electrode and said primary chamber with said roof.

5. In a liquid seal adapted to permit movement of an electrode through an opening in a furnace roof without the passage of fluid from said furnace between said electrode and said roof, the combination which comprises a primary chamber around said electrode, a movable secondary chamber within said primary chamber and extending therefrom, a movable tertiary chamber within said secondary chamber and extending therefrom, a liquid inlet into the top of said tertiary chamber, liquid communicating means between said secondary chamber and said primary chamber, a liquid outlet near the top of said primary chamber, elements attached to the exterior of said tertiary chamber and said secondary chamber adapted to respectively engage the top of said secondary chamber and said primary chamber as said seal is extended, elements attached to the exterior of said secondary chamber and said tertiary chamber adapted to respectively engage the top of said primary chamber and said secondary chamber as said seal is contracted, and means for connecting the top of said tertiary chamber with said electrode and said primary chamber with said roof.

STANFORD A. HARDIN. 

